Brown-skinned, blue-eyed, Y-haplogroup C-bearing European hunter-gatherer from Spain

[Angela]

Quite a heated thread.

@Angela, I am not such a frequent visitor and since I will readily admit being slightly lazy, would you find it terribly bothersome to repost links to some information that is known about skin color and genetics you refer to?

Furthermore I found this:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3694299/#!po=46.4286

The article is about improvements to predictions of eye and skincolor based on DNA. It uses the same genes to try and predict skin color as Lazardis used. It has quite an interesting table, table 3, which states that these predictions are often fairly accurate. Inconclusives seems largest at the skin color that is considered typical for the group. However that result changes with a population this article calls "mixed", the number of inconclusives from mixed populations is large with all skin types. Overal a quarter seems inconclusive.

That does give the impression that the clear warning given in a number of papers about drawing conclusions from these genes probably is not due to being overly careful.

It remains interesting, though, that at the very least the mutations that cause the light skin color in caucasians *nowadays* have spread only fairly recently, but can be found almost universally in that population.

This is Norton et al. 2007. Genetic Evidence for the Convergent Evolution of Light Skin in Europeans and East Asians
The supplementary table is also interesting. They cite any paper worth reading prior to 2007. In finding a correlation between MATP (SLC42A5) and lighter skin in African-Americans, they used a spectrometer. FWIW, they found no evidence for selection at the MCIR locus globally.
http://mbe.oxfordjournals.org/content/24/3/710.full

This is Razib Khan discussing the paper
http://blogs.discovermagazine.com/g...hylogeny-history-and-adaptation/#.U3O05SidIcZ

Other people chime in:
http://www.livescience.com/42838-european-hunter-gatherer-genome-sequenced.html

A genome-wide association study identifies novel alleles associated with hair color and skin pigmentation, Jiali Han,
http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000074

Lucotte et al on the SLC45A2 gene, 2010:
http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000074

Lucotte et al 2011
http://www.saitou-naruya-laboratory.org/assets/files/pdf/Yuasa_AnnHumGenet06.pdf

Genetic Architecture of Skin and Eye Color in an African-European Admixed Population, Sandra Beleza, 2013
http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003372

Direct evidence for positive selection of skin, har and eye pigmentation in Europeans during the last 5,000 years, Sandra Wilde,2014
http://www.pnas.org/content/early/2014/03/05/1316513111.abstract

Molecular Phylogeography of a Human Autosomal Skin Color Locus Under Natural Selection, Victor A. Canfield
As discussed by Dienekes
http://dienekes.blogspot.com/2014/01/slc24a5-light-skin-pigmentation-allele.html

For correlation of the snps with phenotypic expression:
Molecular Genetics of Human Pigmentation Diversity, Richard Sturm, http://hmg.oxfordjournals.org/content/18/R1/R9.full

 

[Angela]

Red hair is extremely rare world wide, and I would maintain it is also very 'infrequent' Europe wide. It reaches frequencies of 10-13% only in parts of Ireland and Scotland, and in Wales and Udmurt areas in Russia. Just weight the areas for population and I think it's clear. In Liguria the range is from 1-2%, but in certain mountain villages it can be 50%.

 

[Aberdeen]

Red hair is extremely rare world wide, and I would maintain it is also very infrequent Europe wide. It reaches frequencies of 10-13% only in parts of Ireland and Scotland, and in Wales and Udmurt areas in Russia. Just weight the areas for population and I think it's clear.

An estimated 4-6% of the European population as a whole have red hair. In Scotland, 13% have red hair and 40% have the recessive redhead gene. For Ireland, the figures are 10% and 46%. So, not extremely rare. It would be quite easy to find enough subjects with red hair to study the issue and determine to what extent the redhead mutation affects skin colour. Probably somewhat but not nearly as much as the two mutations generally considered responsible for depigmentation. One way to study the issue would be to compare pale skinned redheads from Scotland or Ireland with redheaded Berbers, since there are a few redheads among the Berbers but they apparently aren't any lighter skinned than other Berbers.

Anyone who doesn't think that the 45th parallel isn't relevant for frequency of red hair obviously hasn't looked at the facts, and should read what Maciamo has written on the subject.

 

[Angela]

That is true; The Mongoloids have diff. mutations than the Caucasoids but have similar social-structures (even in the Steppes with pure pastoralism); What causes the cline between Koreans and Cherokee for example i have no clue; But what causes the cline between North Europe and South Europe is obviously also manifested in the general cline of lighter-eyes i.e. rs12913832 (G/G) which also factors into skin-lightness;
http://browser.1000genomes.org/Homo...8366118;v=rs12913832;vdb=variation;vf=9155714

I think the cline for eye color is a little different than the one for skin color. However, in general terms my working hypothesis is that this is connected with UV radiation levels.

This is the table from Lucotte et al which lists the frequency for SLC42A5 for various regions in Europe:

This is a map of UV radiation:

 

[Fire Haired14]

I think the cline for eye color is a little different than the one for skin color. However, in general terms my working hypothesis is that this is connected with UV radiation levels.

This is the table from Lucotte et al which lists the frequency for SLC42A5 for various regions in Europe:

This is a map of UV radiation:

This is because of hair color difference, not skin color difference. Are over 50% of Middle easterns as light skinned as north Europeans? According to current knowledge they should be. There are unknown SNPs that can explain the variation of skin color in west Eurasia.

 

[Nobody1]

@Angela

Yes the North/South cline is also manifested by rs16891982 G/G cline but keeping in mind that South Europeans are majority G/G (80-90%) that would not explain the general cline but just for a minority; Whereas rs12913832 (G/G) is a much more drastic cline which effects the masses on either side and thus more (in my opinion) of a decider in North/South than rs16891982; Also rs16891982 G/G levels were found in South Europe as high as 96% in North Italy (Norton 2007 / n=48) and 93-94% in Tuscany/TSI (Norton 2007 / n=16) (1000Genomes / n=98) http://browser.1000genomes.org/Homo...3952193;v=rs16891982;vdb=variation;vf=9666045

I dont see a correlation to UV radiation/sun-exposure; For that only influences the tanning levels and might cause a higher skin cancer risk and blinding effect (light eyes) etc. but wont corrupt ones genetics (i.e. inherited SNPs); What caused these Mutations in the evolutionary process i have no clue; Maybe ancestral Nutrition and inherited henceforth;

 

[Angela]

This is because of hair color difference, not skin color difference. Are over 50% of Middle easterns as light skinned as north Europeans? According to current knowledge they should be. There are unknown SNPs that can explain the variation of skin color in west Eurasia.

This is why I got so snarky with you you when you said I didn't post sources for my statements.

What's the point of posting sources if you don't read them and continue to blow smoke about these issues.

LOOK at the table. It is about SLC42A5. It is a gene PRIMARILY involved in skin pigmentation.
If you had bothered to READ the papers, you would know that they are talking almost exclusively about SKIN pigmentation. What do you think they are using reflectance tests and spectrometers to measure?

Baseless, made up comments like this make it impossible to take any of your posts seriously, and in the future I won't waste my time reading them.

 

[Angela]

@Angela

Yes the North/South cline is also manifested by rs16891982 G/G cline but keeping in mind that South Europeans are majority G/G (80-90%) that would not explain the general cline but just for a minority; Whereas rs12913832 (G/G) is a much more drastic cline which effects the masses on either side and thus more (in my opinion) of a decider in North/South than rs16891982; Also rs16891982 G/G levels were found in South Europe as high as 96% in North Italy (Norton 2007 / n=48) and 93-94% in Tuscany/TSI (Norton 2007 / n=16) (1000Genomes / n=98) http://browser.1000genomes.org/Homo...3952193;v=rs16891982;vdb=variation;vf=9666045

I dont see a correlation to UV radiation/sun-exposure; For that only influences the tanning levels and might cause a higher skin cancer risk and blinding effect (light eyes) etc. but wont corrupt ones genetics (i.e. inherited SNPs); What caused these Mutations in the evolutionary process i have no clue; Maybe ancestral Nutrition and inherited henceforth;

I don't see it that way. At least not based on the papers I've read so far. Mutations, from everything I know about evolution, are random. Positive selection works by selecting for those random mutations that are advantageous. From the discussions in the papers, that is what happened with these mutations.

Prior theories had held this happened tens of thousands of years ago, in reaction to low UV levels in northern Eurasia. Since we are finding Northern Eurasians from Mal'ta to La Brana who don't carry the genes which have been show to correlate with pale skin in modern Europeans, many of these scientists are proposing that a high meat and fish diet provided enough Vitamin D (along with the fact that their bodies were covered for most of the year) that the mutations did not spread through natural selection at that time. (The Eskimos and the SAAMI to a lesser extent are a good example of populations living in far northern Eurasia who have retained more darkly pigmented skin despite the UV levels,but they also consume mostly fish and meat.)

The authors of the papers examining this issue are therefore proposing that the spread had something to do with the diet of the first agriculturalists, which was very low in Vitamin D because they ate next to no fish, for example. The depigmentation snps therefore spread as a result of positive selection. This is all gone through in much more detail in some of the papers. Nothing that I read in them indicates that this effect is limited to the tanning genes. On the contrary, they specifically discuss positive selection in terms of SLC 42A5, which, given that 97% of Europeans are homozygous for SLC24A5, seems to be the prime candidate for this selection differentiation in Europe.

If I don't get too sleepy, I'll try to locate the specific passages where this is discussed.

 

[Nobody1]

I don't see it that way. At least not based on the papers I've read so far. Mutations, from everything I know about evolution, are random. Positive selection works by selecting for those random mutations that are advantageous. From the discussions in the papers, that is what happened with these mutations.

Prior theories had held this happened tens of thousands of years ago, in reaction to low UV levels in northern Eurasia. Since we are finding Northern Eurasians from Mal'ta to La Brana who don't carry the genes which have been show to correlate with pale skin in modern Europeans, many of these scientists are proposing that a high meat and fish diet provided enough Vitamin D (along with the fact that their bodies were covered for most of the year) that the mutations did not spread through natural selection at that time. (The Eskimos and the SAAMI to a lesser extent are a good example of populations living in far northern Eurasia who have retained more darkly pigmented skin despite the UV levels,but they also consume mostly fish and meat.)

The authors of the papers examining this issue are therefore proposing that the spread had something to do with the diet of the first agriculturalists, which was very low in Vitamin D because they ate next to no fish, for example. The depigmentation snps therefore spread as a result of positive selection. This is all gone through in much more detail in some of the papers. Nothing that I read in them indicates that this effect is limited to the tanning genes. On the contrary, they specifically discuss positive selection in terms of SLC 42A5, which, given that 97% of Europeans are homozygous for SLC24A5, seems to be the prime candidate for this selection differentiation in Europe.

If I don't get too sleepy, I'll try to locate the specific passages where this is discussed.

Those are good points and i actually see it similar (Nutrition/VitD necessity/selection/agricultural spread) but i see it less with UV radiation whether high or low; Good examples of that (you used) were the Inuits (Saqqaq) or the Paleolithic Siberian MA1; But is it known whether they were rs1545397 T/T or things of this nature;

 

[LeBrok]

Those are good points and i actually see it similar (Nutrition/VitD necessity/selection/agricultural spread) but i see it less with UV radiation whether high or low; Good examples of that (you used) were the Inuits (Saqqaq) or the Paleolithic Siberian MA1;

Their everyday staple was fresh liver. Liver is a storage of vitamin D3, and many other elements, so as such it is one of the best sources of vitamin D. Inuits can't stay healthy without this diet, especially pregnant women and young offspring. If they had changed lifestyle to farming and farmers diet, they would need to get much lighter and get needed D3 from suntanning during summer to survive.
Basically this is what happened in farming societies in Europe and North East Asia.

 

[Grubbe]

I'm confused. My initial comment on this thread addressed the fact that it was basically a duplicate topic.

Nevertheless, here's a few additional quips....

1. I've never seen an actual person look like this poor fellow (other than this photo). Strangely enough, the individual with the heaviest amount of freckling I've ever encountered in real life (and he had but a small fraction of freckles compared to our afflicated subject) was 100% Irish. Go figure.

2. We may not be defining sexual selection in the same way... let's use a hypothetical case. It's 1,100 years ago and we're sitting on the banks of the Volga. A Swedish Viking party drifts by and we watch as they are busy dividing their recently captured female slaves from a raiding party into "keepers" (ie. breeding partners) and ones that will be taken to market in Constantinople. We notice an obvious trend in their decision making...

What if these Vikings keep all the blonde haired, blue-eyed buxom women for themselves and trade the darker, brunette females for silver... is this sexual selection? I would think so. Before you dismiss this scenerio as farcical... please review the Norse tales of Rig.

Of course this Viking raiding party would have taken place a few thousand years AFTER my proposed SLC positive group first arrived in what we now call Europe. The selective actions of this hypothetical Viking construct would only further accent the pigmentation differences we see in Northern climes (or rather lack of pigmentation we see in the North).

Since there are quite a few dark haired people in the Scandinavian countries today, I presume many of these viking folks liked brunettes too! More than sexual selection for specific traits, I find it more probable that most has boiled down to power and/or money. Just look around and see which men gets the beauties today. Many of these men are very, very far from handsome looking.

 

[Drac II]

This is a map of UV radiation:

For the umptieth time already: this is NOT a UV radiation map. UV radiation levels keep changing every day for any given area. These are the levels for today in Europe:

http://www.havaturkiye.com/images/charts/en/contour/20140514/euro/euro/1400051573/uv.gif

While only 3 days ago they were like this:

http://www.havaturkiye.com/images/charts/en/contour/20140511/euro/euro/1399835442/uv.gif

And if you check tomorrow or in a couple of days, they will have shifted again.

 

[Angela]

For the umptieth time already: this is NOT a UV radiation map. UV radiation levels keep changing every day for any given area. These are the levels for today in Europe:

http://www.havaturkiye.com/images/charts/en/contour/20140514/euro/euro/1400051573/uv.gif

While only 3 days ago they were like this:

http://www.havaturkiye.com/images/charts/en/contour/20140511/euro/euro/1399835442/uv.gif

And if you check tomorrow or in a couple of days, they will have shifted again.

Quite spoiled my morning coffee. And here people were having a relatively rational discussion.

And what the heck happened to my ignore list?:startled:

 

[Drac II]

This is because of hair color difference, not skin color difference. Are over 50% of Middle easterns as light skinned as north Europeans? According to current knowledge they should be. There are unknown SNPs that can explain the variation of skin color in west Eurasia.

You can tell how unreliable these few SNPs are for determining actual OBSERVED skin pigmentation in any population from studies that have actually bothered to measure the samples with skin reflectance. Candille et al. 2012 did just that and the actual observed results did not go entirely well with the "predictions" based on frequencies of a few SNPs.

 

[Angela]

For the umptieth time already: this is NOT a UV radiation map. UV radiation levels keep changing every day for any given area. These are the levels for today in Europe:

http://www.havaturkiye.com/images/charts/en/contour/20140514/euro/euro/1400051573/uv.gif

While only 3 days ago they were like this:

http://www.havaturkiye.com/images/charts/en/contour/20140511/euro/euro/1399835442/uv.gif

And if you check tomorrow or in a couple of days, they will have shifted again.

For the UMPTEENTH time, these are ANNUAL levels.

http://www.greenrhinoenergy.com/solar/radiation/empiricalevidence.php

 

[Nobody1]

The reflectance-method used by Candille, Jablonski and Rindermann are highly corruptible by tanning levels (as noted by Candille); The more tanned the darker and since none of the people tested are from any study groups (i.e. have the same levels/conditions of testing) you get the results that the Portuguese are lighter than the Polish or that the Spanish are lighter than some British when in fact they are just less tanned; On the other hand the SNPs (8-plex etc.) are highly reliable because they are not corruptible by any outside factors and have an accuracy of 99% (skin-color); Best example is Candille and her SNP results for the actual basal skin-tone (no tanning) Polish 98% (lightest) and Portuguese 88% (darkest);

 

[Greying Wanderer]

An estimated 4-6% of the European population as a whole have red hair. In Scotland, 13% have red hair and 40% have the recessive redhead gene. For Ireland, the figures are 10% and 46%. So, not extremely rare. It would be quite easy to find enough subjects with red hair to study the issue and determine to what extent the redhead mutation affects skin colour. Probably somewhat but not nearly as much as the two mutations generally considered responsible for depigmentation. One way to study the issue would be to compare pale skinned redheads from Scotland or Ireland with redheaded Berbers, since there are a few redheads among the Berbers but they apparently aren't any lighter skinned than other Berbers.

Anyone who doesn't think that the 45th parallel isn't relevant for frequency of red hair obviously hasn't looked at the facts, and should read what Maciamo has written on the subject.

But when?

At the LGM were the levels of low UV much further south?

If the low UV / cloudiness extended further south at the LGM and then gradually retreated north then that would be another possible explanation of the red distribution i.e. it was more widespread in the past and has been retreating northwards.

 

[Greying Wanderer]

I don't see it that way. At least not based on the papers I've read so far. Mutations, from everything I know about evolution, are random. Positive selection works by selecting for those random mutations that are advantageous. From the discussions in the papers, that is what happened with these mutations.

Prior theories had held this happened tens of thousands of years ago, in reaction to low UV levels in northern Eurasia. Since we are finding Northern Eurasians from Mal'ta to La Brana who don't carry the genes which have been show to correlate with pale skin in modern Europeans, many of these scientists are proposing that a high meat and fish diet provided enough Vitamin D (along with the fact that their bodies were covered for most of the year) that the mutations did not spread through natural selection at that time. (The Eskimos and the SAAMI to a lesser extent are a good example of populations living in far northern Eurasia who have retained more darkly pigmented skin despite the UV levels,but they also consume mostly fish and meat.)

The authors of the papers examining this issue are therefore proposing that the spread had something to do with the diet of the first agriculturalists, which was very low in Vitamin D because they ate next to no fish, for example. The depigmentation snps therefore spread as a result of positive selection. This is all gone through in much more detail in some of the papers. Nothing that I read in them indicates that this effect is limited to the tanning genes. On the contrary, they specifically discuss positive selection in terms of SLC 42A5, which, given that 97% of Europeans are homozygous for SLC24A5, seems to be the prime candidate for this selection differentiation in Europe.

If I don't get too sleepy, I'll try to locate the specific passages where this is discussed.

It does seem plausible that coastal populations wouldn't need to develop lighter skin to thrive in the north so the question shifts to how did more inland populations cope?

edit: Just to add to the point about the Saami, there's been an idea for a long time that the Welsh, particularly north Welsh were an older and darker strain so they might turn out to be another data point.

 

[Drac II]

The reflectance-method used by Candille, Jablonski and Rindermann are highly corruptible by tanning levels (as noted by Candille); The more tanned the darker and since none of the people tested are from any study groups (i.e. have the same levels/conditions of testing) you get the results that the Portuguese are lighter than the Polish or that the Spanish are lighter than some British when in fact they are just less tanned; On the other hand the SNPs (8-plex etc.) are highly reliable because they are not corruptible by any outside factors and have an accuracy of 99% (skin-color); Best example is Candille and her SNP results for the actual basal skin-tone (no tanning) Polish 98% (lightest) and Portuguese 88% (darkest);

We've been over this before. No, the possible interference of tanning is avoided by taking measurements from the usually unexposed parts of the body (armpits or pelvis area.) This preventive measure has been practiced since at least the anthropology of the 19th century, and I have even seen 18th century writers touching upon the subject of human differences clearly notice that unexposed parts of the body are lighter than the exposed ones, so this basic fact was already noticed quite a long time before our current times. Candille et al's results prove in fact that you can't rely on a few SNPs to make accurate "predictions" when it comes to pigmentation. According to them, the Portuguese should have been the darkest skinned on average among their sampled populations, but they were shown not to be so when the skin reflectance from unexposed areas of the body were measured, it was the Italians who scored the lowest, despite having a higher frequency of the few SNPs that this study took into account as having to do with light skin. The "prediction" simply did not match the actual observed results.

 

[Drac II]

For the UMPTEENTH time, these are ANNUAL levels.

http://www.greenrhinoenergy.com/solar/radiation/empiricalevidence.php

For the MEGA-UMPTIETH time, no, that link and map are not about UV Index but about solar irradiance in general. UV rays are part of sunlight, and it is them that affect the skin, not all solar light:

http://www.skincancer.org/prevention/uva-and-uvb/understanding-uva-and-uvb

The levels of UV rays vary throughout the year, and in fact they have been increasing and decreasing over different areas:

http://wwws1.eea.europa.eu/publications/92-9167-205-X/fig9.3.gif

A lot of Europe has been receiving more UV rays in the past few decades than previously.